I am so sorry to read that you've been sick. I do hope that you are taking care of yourself and taking things slowly so that you can get back up on your feet.
I agree w/what you posted about the family dynamics. I know that my former h's family was a train wreck. Many of them divorcing, having affairs, etc., and didn't think anything of it. My xh's father had been married 5 times and had affairs in between the marriages and no one blinked an eye. It's sad what can happen to families, but more importantly the children that have to live in such a state.
I know that you are going to be the best dad and supportive of your daughters. You are their rock, so it's important to take care of yourself, get back on your feet and enjoy the time you have w/them. They grow up so fast.
Please take care of yourself.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.